Final Test Flashcards
- Give a biological example for each property/processes associated with life that we covered in class.
Give examples that are different from those in the book and used in class. ***
- energy : they acquire and use energy ie. photosynthesis, respiration, fermentation, digestion
- cells : made up of membranebound
units that regulate the passage of materials between exterior and
interior spaces - information : process hereditary / genetic information encoded in genes. ie. DNA, RNA
- replication : every organism replicates itself; reproduction
- evolution : organisms are the product of evolution, and populations continue to evolve; ie. giraffe with
tongue that can eat thorny plants COOL!
- In science, what is a hypothesis, and what is a theory? (see pages 78).
How are they different?
hypothesis : testable statement to explain phenomena or observations must
be testable and falsifiable
theory : an explanation for a very general class of phenomena or observations that are supported by a wide body of
evidence. Proposed explanations for broad patterns in nature
- What is a “control” in an experiment? Why is it important?
checks for factors, other than the one being tested, that might influence the experiment’s outcome. (also controlling
for the possibility that the manipulation itself affected the behavior)
good experiments :
1. conditions must be constant or equivalent
2. repeating tests is essential
3. must include control groups have
a treatment group and all other variables must be constant (control
treatment group)
- What is the smallest unit of life?
Cell
- What are the two components of cell theory?
Describes
a) what organisms are made up of and b) where they come from
A. Cell theory :
1. all living organisms are made of one or more cells ( You must have a cell in order to make another cell.)
2. all cells come from preexisting cells (If you must have a cell to make another, then all cells must be related
- Approximately 96% of the human body is comprised of what four elements?
hydrogen, carbon, nitrogen, oxygen
- An atom is the smallest unit of matter that still retains the properties of the element. Describe the atomic
structure (the subatomic particles) of a carbon atom. How is it different than a nitrogen atom?
Carbon
has 2 electrons in its innermost shell and 4 in its valence shell.
Nitrogen
has 2 electrons in its innermost shell and 5 in its valence shell.
Nitrogen
has one more proton, electron, and neutron than Carbon.
C6 N7 O8
- What are valence electrons? What is the valence number of Oxygen? Draw an electron distribution
diagram. Can you do this for the first 15 elements in the periodic table?
valence : number of unpaired electrons found in the outermost layer of an electron shell.
The
valence number of Oxygen is 6 (there is 8 protons in Oxygen).
Yes
I can! lol
- What is a covalent bond? What is the difference between a nonpolar and polar covalent bond?
covalent bond : electrical attractions and repulsion (as two atoms move together, their positively charged nuclei
repel each other and their negatively charged electrons repel each other — bonds happen when attractive forces
overcome repulsive forces); atoms become more stable by making covalent bonds and sharing their electrons in the
valence shell, which glues two atoms together
1. nonpolar covalent (ie. hydrogen molecule): electrons halfway b/t 2 atoms, shared equally;
2. polar covalent (h2o); electrons shared unequally and one side is more electronegative and there’s partial
charges on atoms; asymmetric sharing of electrons; Water is an example of a polar molecule. equal
electronegativity between atom’s electrons that are shared equally or symmetrically Oil
is an example of
an nonpolar molecule(this is why water and oil do not mix). Nice
- What is an ion? How is an ionic bond different than a covalent bond?
ionic bonds: electrons are completely transferred from one atom to the other
anion : negatively charged ion
cation : positively charged ion
range from equal electron sharing (nonpolar covalent) to unequal sharing (polar covalent bonds)
Ionic bond isn’t sharing, it’s stealing electrons
bonds in order of strength (less to more):
1. van der waals forces
2. hydrophobic / hydrophilic interactions
3
3. hydrogen bonds
4. ionic bonds
5. covalent bonds
Difference between nonpolar/polar covalent bonds depend on the difference in electronegativities of the bonded
atoms. When the difference of electronegativity is 1 or greater, such as between oxygen and hydrogen, then the
covalent bond is polar.
- What is an isotope? Give two examples of how are isotopes are useful in the biological sciences.
isotopes (varying neutrons for the same element): most are stable. Isotopes are used in biology for carbon dating
and radioactive tracers in things such as CAT scans.
- Know the terms:
specific heat capacity: the amount of energy required to raise the temperature of 1 gram of a substance by 1 degree
Celsius; water has a high specific heat because hydrogen bonds must be broken before heat can be transferred and
the water molecules begin to move faster. As molecules increase in overall polarity (and their ability to form
hydrogen bonds), it takes an extraordinarily large amount of energy to change their temperature
a. surface tension: water organizes to maximize H bonds, breaking bonds requires energy ; enhanced
attraction between the surface of water meniscus results in tension that minimizes the total surface area;
when water molecules are at the surface, there are no water molecules above them for hydrogen bonding,
they exhibit stronger attractive forces between their nearest molecules.
b. adhesion: attraction between unlike molecules, usually analyzed in regard to interactions between a liquid
and a solid surface (water molecules adhere to glass and pull upward at perimeter) chalk on a chalkboard
c. cohesion: attraction between like molecules (water is cohesive because it stays toughener because of the
hydrogen bonds that form between individual molecules); water molecules at surface form H bonds with
water molecules and resist the upward pull of adhesion; allows capillary action water
attracted to objects
with electric charge
- How does hydrogen bonding contribute to the properties of adhesion and cohesion? Why are adhesion and
cohesion important in biological systems?
adhesion: attraction between unlike molecules, usually analyzed in regard to interactions between a liquid and a
solid surface. Hydrogen bonding in between water molecules that makes ice solid (intermolecular force) contributes
to adhesion. Water liquid has less hydrogen bonding in between each molecules compared to ice.
Within
a meniscus, adhesion pulls upward at the perimeter of a glass test tube.
cohesion: attraction between like molecules (water is cohesive because it stays toughener because of the hydrogen
bonds that form between individual molecules). Not only can water hydrogen bond with each other but water
molecules can also hydrogen bond with other polar molecules (such as glass).
adhesion + cohesion: Within
a meniscus, cohesion resists the upward pull of adhesion.
- How does hydrogen bonding contribute to the property of surface tension? How does this help us
understand how a water strider can keep from sinking as it travels across the surface of a pond?
Water resists any force that increases its surface area — any force that depresses a water surface meets with
resistance, making a water surface act like an elastic membrane
- Water has occasionally been called the “universal solvent”. It is not really “universal” but it is a very good
solvent for many substances. What properties of water make it a good solvent?
why water is such an effective solvent:
1. both of the OH
bonds are polar, so the oxygen atom has a partial negative charge and hydrogen has a
partial positive
2. molecule is bent — the partial negative charge sticks out from the partial positive charges, giving it overall
polarity
